Signal transduction is any process by which a cell converts one kind of signal or stimulus into another. One class of molecules involved in signal transduction is the kinase family of enzymes.
Protein kinases are a large class of enzymes which catalyze the transfer of the □-phosphate from ATP to the hydroxyl group on the side chain of Ser/Thr or Tyr in proteins and peptides and are intimately involved in the control of various important cell functions, perhaps most notably: signal transduction, differentiation, and proliferation.
Phosphorylation of proteins by kinases is an important mechanism in signal transduction for regulation of enzyme activity. The tyrosine kinases are divided into two groups; those that are cytoplasmic proteins and the transmembrane receptor-linked kinases.
Because kinases are involved in the regulation of a wide variety of normal cellular signal transduction pathways (e.g., cell growth, differentiation, survival, adhesion, migration, etc.), kinases are thought to play a role in a variety of diseases and disorders. Thus, modulation of kinase signaling cascades may be an important way to treat or prevent such diseases and disorders. One promising potential therapeutic use for protein kinase or protein phosphatase inhibitors is as anti-cancer agents.
Small molecule interference with tubulin dynamics has broad and profound effect on a cell. When small molecules bind to tubulin they can interfere with the dynamics of microtubules formed from tubulin, either by stabilizing the formed microtubules so they cannot break down or by preventing new formation of microtubules by polymerization.
The effect of small molecules interfering with tubulin dynamics can manifest in the suppression of the cell's ability to proliferate. Interference by small molecules on tubulin dynamics can force the cell to arrest at the G2/M point in the cell cycle, ceasing mitosis, and triggering apoptosis. This action makes these small molecules efficacious in treating human diseases associated with uncontrolled cell proliferation. Efficacy in treating hyper-proliferative disorders has been proven by compounds such as Paclitaxel (a microtubule stabilizer) and Vinblastin (a tubulin polymerization inhibitor) in human subjects.
Tubulin-targeting small molecules can also affect vascularization of tissue. Several tubulin polymerization inhibitors have been demonstrated to affect the abnormal vascularization of tumors. These effects manifest in, e.g., normalization of the vascular network and cutting off blood flow to cancerous tumors, resulting in necrosis. These vascular effects may also be useful for other disease states resulting from abnormal vascularization, such as ocular myopathy.
There is a need for small molecule compounds that modulate the kinase signaling cascade as well as tubulin dynamics. The present application addresses such need.